Accumulator with inlet diffuser\diverter

ABSTRACT

An accumulator for use in a motor vehicle air conditioning system. The accumulator comprises an accumulator housing, an outlet fluid pipe assembly and an inlet fluid pipe assembly. The accumulator housing has a top wall, a bottom wall and a side wall connecting the top wall to the bottom wall. The outlet fluid pipe assembly has an inlet end. The inlet fluid pipe assembly includes a tubular first portion and a diverter/diffusing portion configured to direct refrigerant flowing through the first portion towards the sidewall and downwardly away from the top wall of the accumulator housing. The first tubular portion has an axis offset from the inlet end of the outlet fluid pipe assembly.

BACKGROUND OF THE INVENTION

[0001] The present invention relates to an accumulator for use in motorvehicle air conditioning systems. More specifically, it relates to thefluid inlet pipe assembly used in such accumulators.

[0002] In air conditioning systems such as those for motor vehicle use,an accumulator is normally connected between the evaporator and thesuction side of the compressor to prevent liquid refrigerant fromentering the compressor while permitting vaporous refrigerant to pass.This separation of liquid refrigerant, as well as its eventual returninto vaporous form, is accomplished by either a straight or U-shapedfluid outlet pipe whose inlet end is positioned high in the accumulatorso as to be open to receive the vaporous refrigerant flow delivered fromthe evaporator. To separate the liquid refrigerant from the vaporousrefrigerant, a baffle may be mounted either on the ceiling of theaccumulator housing or directly on the inlet end of the fluid outletpipe, as disclosed in U.S. Pat. No. 4,111,005. Alternatively, thebaffle, as a separate part, may be eliminated by forming the inlet endof the fluid outlet pipe with a trumpet shape portion located closelyadjacent to the ceiling of the accumulator housing, as disclosed in U.S.Pat. No. 5,179,844.

[0003] The mixture of liquid and vaporous refrigerant enters theaccumulator through a fluid inlet pipe assembly. The fluid inlet pipeassembly may be attached to the side wall of the accumulator housing, asdisclosed in U.S. Pat. Nos. 4,111,005 and 5,179,844, or alternativelythe fluid inlet pipe assembly may be attached the top wall of theaccumulator housing to reduce the size of the accumulator housing.However, this arrangement of attaching the fluid inlet pipe assembly tothe top wall of the accumulator housing has been found to causeexcessive internal agitation; thus increasing the risk of a mixture ofliquid and vaporous refrigerant passing through the outlet pipe to thecompressor, leading to inefficient operation of the air conditioningsystem and risk of damage to the compressor. To reduce agitation of andfoaming of refrigerant into the interior of the accumulator, U.S. Pat.No. 6,363,742 discloses the use of an inverted T-shaped inlet fluid pipeassembly having two outlet ends facing a portion of the side wall todivert and reduce the energy of the fluid as the fluid enters theaccumulator. While such an inverted T-shaped inlet fluid pipe assemblyis effective in diverting and reducing the energy of the fluid, itsignificantly increases the packaging requirement of the inlet fluidpipe assembly inside the accumulator housing and increases the costassociated with forming a pipe with two ends extending between oppositesides of the side wall. Even though the '742 patent discloses analternative arrangement of an inlet fluid pipe assembly having a singleopen end such that the inlet pipe assembly is substantially L-shapedinside the accumulator housing, the '742 patent does not teach orsuggest how the L-shaped inlet pipe may be capable of diffusing theliquid and vaporous mixture exiting the single open end.

[0004] In addition to turbulent flow caused by the flow of refrigerantout of the inlet fluid pipe assembly, turbulent flow may also be causedby the refrigerant flowing through the flow passage defined within theinlet fitting. Typical, to form a fluid path in the inlet fitting havinga bend, two straight fluid passages are formed in the inlet fitting,wherein the two fluid passages intersects to connect the two straightfluid passages. The straight fluid passages are normally formed bydrilling holes with cutters having sharp conical shaped drill tips. Toassure that the intersection of the cross-drilled holes provide asufficient size opening to connect the holes, each hole is drilled suchthat circumferential portion of the cutter extends at least to theintersection of the cross-drilled holes. However, due to the conicalterminal ends of the holes created by the drill tips, sharp edges areoften present at the intersection of the cross-drilled holes causingturbulence and pressure drop in the inlet flow.

BRIEF DESCRIPTION OF THE DRAWINGS

[0005]FIG. 1 is a sectional view of an accumulator with a typical priorart fluid inlet pipe assembly attached to the top wall of theaccumulator housing, along with the other components of an airconditioning system schematically illustrated;

[0006]FIG. 2 is a sectional view of an accumulator with a prior artinverted T-shape fluid inlet pipe assembly attached to the top wall ofthe accumulator housing;

[0007]FIG. 3 is a sectional view of an accumulator with a firstembodiment of a fluid inlet pipe assembly in accordance to the presentinvention;

[0008]FIG. 4 is a perspective view of the fluid inlet pipe assembly ofFIG. 3;

[0009]FIG. 5 is a sectional view of an accumulator with a secondembodiment of a fluid inlet pipe assembly in accordance to the presentinvention;

[0010]FIG. 6 is a sectional view of an accumulator with a thirdembodiment of a fluid inlet pipe assembly in accordance to the presentinvention;

[0011]FIG. 7 is a perspective view of the fluid inlet pipe assembly ofFIG. 6;

[0012]FIG. 8 is a sectional view of an accumulator with a fourthembodiment of a fluid inlet pipe assembly in accordance to the presentinvention;

[0013]FIG. 9 is a perspective view of the diverter/diffuser assembly ofFIG. 8;

[0014]FIG. 10 is a sectional view of an accumulator with a fifthembodiment of a fluid inlet pipe assembly in accordance to the presentinvention;

[0015]FIG. 11 is a sectional view of an accumulator with a sixthembodiment of a fluid inlet pipe assembly in accordance to the presentinvention;

[0016]FIG. 12 is a front view of a typical prior art inlet fitting;

[0017]FIG. 13 is a sectional view of the prior art inlet fitting of FIG.12 as taken along line 13-13;

[0018]FIG. 14 is a front view of an inlet fitting in accordance a secondaspect of the present invention; and

[0019]FIG. 15 is a sectional view of the inlet fitting of FIG. 14 astaken along line 15-15.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0020] A sectional view of an accumulator for a motor vehicle airconditioning system 10, with a typical prior art fluid inlet pipeassembly attached to the top wall of the accumulator housing, isillustrated in FIG. 1, along with the other components of the airconditioning system schematically illustrated. The air conditioningsystem 10 includes an accumulator 12 for separating the liquidrefrigerant from the vaporous refrigerant, a compressor 14 for pumpingand pressurizing the vaporous refrigerant, an outside heat exchanger orcondenser 16 located outside the passenger compartment to cool andliquify the hot vaporous refrigerant from the compressor 14, an expander18 to lower the pressure of the liquid refrigerant, and an inside heatexchanger or evaporator 20 which absorbs heat from the air passingbetween the tubes of the evaporator 20, thus cooling the air flowinginto the passenger compartment. The air condition system 10 is a closedloop system wherein the refrigerant flows from the accumulator 12, tothe compressor 14, to the condenser 16, to the expander 18, to theevaporator 20, and back to the accumulator 12.

[0021] The accumulator 12 as illustrated in FIG. 1 includes apermanently assembled housing 22 comprised of upper and lower portions24, 26 which are each normally closed at one end and open at the otherend, and are adapted to be telescopically received together and joinedat their open ends. The upper end of the upper portion 24 defines thetop wall 28 of the accumulator housing 22. The inside surface of the topwall 28 defines the ceiling 30 of the interior of the accumulatorhousing 22. The bottom end of the bottom portion 26 defines the bottomwall 32 of the accumulator housing 22. The cylindrical walls of theupper portion 24 and the lower portion 26 define the side wall 34 of theaccumulator housing 22 connecting the top wall 28 to the bottom wall 32.An inlet fitting 36, by which the accumulator 12 is connected to theevaporator 20, is attached to the top wall 28 of the accumulator housing22. An outlet fitting 38, by which the accumulator 12 is attached to thecompressor 14, is attached to the side wall 34 of the accumulatorhousing 22.

[0022] Located within the interior of the accumulator housing 22, aninlet fluid pipe assembly 40 is attached to the inlet fitting 36 and aU-shaped outlet fluid pipe assembly 60 is attached to the outlet fitting38. The inlet fluid pipe assembly 40 includes a straight tubularvertical portion 42 having an outlet end 48 located a given distancefrom the ceiling 30 of the accumulator housing 22. The outlet end 48 ofthe vertical portion 42 is directed downwardly toward the bottom wall 32of the accumulator housing 22. The U-shaped outlet fluid pipe assembly60 includes an outlet end 62 that is press fitted into the outletfitting 38. The outlet fluid pipe assembly 60 further includes adownward leg 64 that extends from the outlet fitting 38 to a pointadjacent to the bottom wall 32, a return bend 66 that makes a turn nearthe bottom wall 32 of the accumulator housing 22, and upward leg 68 thatextends upwardly and terminates at an inlet end 70 adjacent the ceiling30 of the housing 22. The inlet end 70 of the outlet fluid pipe assembly60 is formed with a trumpet or flared shape portion 72 that is locatedabove the outlet end 48 of the inlet fluid pipe 40 with its rim 74 closethe ceiling 30 of the accumulator housing 22.

[0023]FIG. 2 illustrates an accumulator 112 with a prior art invertedT-shaped fluid inlet pipe assembly 140 attached to the top wall 128 ofthe accumulator housing 122, as disclosed in U.S. Pat. No. 6,363,742.The inlet pipe assembly 140 includes a vertical portion 142 and ahorizontal portion 146. One end of the vertical portion 142 extendsthrough the top wall 128 of the accumulator housing 122 and the otherend of the vertical portion 142 is attached to middle of the horizontalportion 146. The horizontal portion 146 can be viewed as two horizontalsub-portions 146 a, 146 b extending radially outwardly at oppositedirections from the end of the vertical portion 142 at 90 degree angles.Since the axis of the vertical portion 142 of the inlet pipe assembly140 is approximately parallel with the axis of the accumulator housing122, the axis of the horizontal portion 146 is approximately 90 degreesto the side wall 134 of the accumulator housing 122.

[0024]FIGS. 3 and 4 illustrate a first embodiment of a fluid inlet pipeassembly 240 according to the present invention. The fluid inlet pipeassembly 240 is attached to the top wall 228 of the accumulator housing222. The fluid inlet pipe assembly includes a tubular vertical portion242, a tubular diverter/diffuser portion 246 and a curved portion 244connecting the vertical portion 242 to the diverter/diffuser portion246. The vertical portion 242 has an axis approximately parallel withthe axis of the accumulator housing 222. To allow the inlet end 270 ofthe outlet pipe assembly 260 to be located near the ceiling of theaccumulator housing 222, the axis of the vertical portion 242 is offsetfrom the inlet end 270 of the outlet pipe assembly 260. In other words,the axis of the vertical portion 242 does not intersect the inlet end270 of the outlet pipe assembly 260. Such an arrangement allows theinlet end 270 of the outlet pipe assembly 260 to be located adjacent tothe vertical portion 242 of the inlet pipe 240, rather than, below thevertical portion 242 of the inlet pipe 240.

[0025] The axis of the divert/diffuser portion 246 is at an anglegreater than 0 degree and less than 90 degrees from the axis of verticalportion. The angle α from the axis of the diverter/diffuser portion 246to the axis of the vertical portion 242 is preferably between 10 degreesto 80 degrees, and more preferably between 15 degrees to 45 degrees. Theembodiment of FIG. 3 illustrates the angle α from the axis of thediverter/diffuser portion 246 to the axis of the vertical portion 242 atapproximately 30 degrees. By bending the pipe for forming the inlet pipeassembly 240 at an angle less than 90 degrees, the flow of the inletrefrigerant mixture is directed towards the side wall 234 and dowardlyaway from the ceiling 230 of the accumulator housing 222. By directingthe inlet refrigerant mixture towards the side wall 234, the liquidrefrigerant is able to flow downwardly along the side wall 234 to thebottom sump portion of the accumulator housing 222. By directing theinlet refrigerant mixture downwardly away from the ceiling 230 of theaccumulator housing 222, the possible of the inlet refrigerantunintentionally entering the inlet end 270 of the outlet fluid pipeassembly 260 is reduced.

[0026] The terminal end of the diverter/diffuser portion 246 defines theoutlet end 248 of the fluid inlet pipe assembly 240. The outlet end 248of the fluid inlet pipe assembly 240 is formed by making an angular cutacross the diverter/diffuser portion 246 such that the plane of the cutis approximately parallel of the axis of the vertical portion 242. Sincethe axis of the diverter/diffuser portion 246 is at an angle less than90 degrees from the axis of the vertical portion 242 and the plane ofthe cut is made approximately parallel of the axis of the verticalportion 242, the cut will be at an angle other than 90 degrees from theaxis of the diverter/diffuser portion 246. With the cut at angle otherthan 90 degrees from the axis of the diverter/diffuser portion 246, theoutlet end 248 of the fluid inlet pipe assembly 240 has across-sectional area greater than the average cross-sectional areaperpendicular to the axis of the vertical portion 242. With the outletend 248 having a greater cross-sectional area, the outlet end 248 isable to act as a diffuser diffusing the flow of refrigerant coming outthe outlet end 248; thus, reducing or preventing turbulent flow ofrefrigerant. Another advantage of cutting the diverter/diffuser portion246 at a plane approximately equal to the axis of the vertical portion242 of the inlet pipe assembly 240 is that since the axis of thevertical portion 242 of the inlet pipe assembly 240 is approximateparallel to the axis of the accumulator housing 222, the distances fromthe edges of the outlet end 248 to the side wall 234 are approximatelyequal. The approximately equal distances allow for a more even flow ofliquid refrigerant between the outlet end 248 of the inlet pipe assembly240 and the side wall 234 of the accumulator housing 222.

[0027] As illustrated in FIG. 3, it is desirable for the distance fromthe inlet end 270 of the outlet fluid pipe assembly 260 to the top wall228 of the accumulator housing to be greater than the distance from theoutlet end 248 of the inlet fluid pipe assembly 240 to the top wall 228of the accumulator housing. This arrangement further reduces thepossibility of inlet refrigerant from unintentionally entering the inletend 270 of the outlet fluid pipe assembly 260.

[0028]FIG. 5 illustrates a second embodiment of a fluid inlet pipeassembly according to the present invention. The fluid inlet pipeassembly 340 is similar to the fluid inlet pipe assembly 240 of thefirst embodiment except the cut forming the outlet end 348 of the fluidinlet pipe assembly 340 is made in a curved diverter/diffuser portion346 of the fluid inlet pipe assembly 340. In other words, the cutforming the outlet end 348 is made between the tubular vertical portion342 and the center point C1 defining the curvature of the curveddiverter/diffuser portion 346. By forming the outlet end 348 at thecurved diverter/diffuser portion 346 of the inlet pipe assembly 340;similar to the first embodiment, the flow of the refrigerant mixture outof the outlet end 348 is directed towards the side wall 334 so thatentrained liquid will flow dowardly along the side wall 334, anddirected downwardly away from the inlet end 370 the outlet pipe assembly360.

[0029] Furthermore, with the cut for forming the outlet end 348 made ata curved tubular section defining the diverter/diffuser portion 346,similar to the first embodiment, the outlet end 348 of the fluid inletpipe assembly 340 has a cross-sectional area greater than the averagecross-sectional area perpendicular to the axis of the vertical portion342. With the outlet end 348 having a greater cross-sectional area, theoutlet end 348 is able to act as a diffuser diffusing the flow ofrefrigerant coming out the outlet end 348; thus, reducing or preventingturbulent flow of refrigerant.

[0030]FIGS. 6 and 7 illustrate a third embodiment of a fluid inlet pipeassembly 440 according to the present invention. The fluid inlet pipeassembly 440 includes a tubular vertical portion 442 and adiverter/deflecting portion 446. The fluid inlet pipe assembly 440 isformed by first providing a straight pipe. A notch is cut near one endof the pipe leaving a long end at one longitudinal direction from thenotch and a short end at other longitudinal direction for the notch. Thelong end of the pipe defines the vertical portion 442 of the fluid inletpipe assembly 440. The notch can be made such that the notch completelycuts through one longitudinal surface of the short end. Alterative ifthe notch does not completely cut through one longitudinal surface ofthe short end, another cut is made longitudinally along the short end ofthe notched pipe.

[0031] The short end of the pipe is unfolded to form and an unfoldedsection. Depending on how the short end is unfolded, the unfoldedsection can be cylindrical, conical or virtually flat. The unfoldedsection is then bent along the notch to an angle less than 90 degrees todefine the diverter/diffuser portion 446. The angle the axis of thevertical portion 442 from the axis of the diverter/diffuser portion 446is preferably between 10 degrees to 80 degrees, and more preferablybetween 15 degrees to 45 degrees. Similar to the first and secondembodiments, the flow of the refrigerant mixture flowing from thediverter/diffuser portion 446 is directed towards the side wall 434 sothat entrained liquid will flow dowardly along the side wall 434, anddirected downwardly away from the inlet end 470 of the outlet pipeassembly 460. Furthermore, due the diverter/diffuser portion 446 formedby unfolding a section of pipe, the average radius of the inner surfaceof the diverter/diffuser portion 446 is greater than the average radiusof the vertical portion 442. This greater radius of the inner surface ofthe diverter/diffuser portion 446 allows the inner surface of thediverter/diffuser portion to act as a diffuser diffusing the flow ofrefrigerant coming out the outlet end 448; thus, reducing or preventingturbulent flow of refrigerant.

[0032]FIGS. 8 and 9 illustrate a fourth embodiment of a fluid inlet pipeassembly 540 according to the present invention. The fluid inlet pipeassembly 540 has a straight vertical portion 542 attached to the topwall 528 of the accumulator housing 522. The vertical portion 542 has afluid flow opening 543 directed downwardly towards the bottom wall 532of the accumulator housing 522. Attached to the end of the verticalportion 542 is a separate diverter/diffuser assembly 545 having adiverter/diffuser portion 546 for diverting the flow of the refrigerantmixture from the fluid flow opening 543 towards the sidewall 534 so theentrained liquid will flow dowardly along the sidewall 534, and directeddownwardly away from the entrance to the outlet pipe.

[0033] The diverter/diffuser assembly 545 includes a mounting ring 550,a plurality of posts 552 connecting the mounting ring 550 to thediverter/diffuser portion 546. The mounting ring 550 is adapted to bemounted onto and attached to the outer surface of the vertical portion542. The mounting ring 550 has an inner diameter slight larger than theouter diameter of the outer surface of the vertical portion 542. Theinner diameter of the mounting ring 550 should be sized to allow for atight fit between the mounting ring 550 and the vertical portion 542,but still be able to slide over the outer surface of the verticalportion 542 during the mounting process without breaking the mountingring 550. The mounting ring 550 can be attached to the vertical portion542 by glue, welding, brazing, mechanical or other attachment means.Three posts 552 connect the mounting ring 550 to the diverter/diffuserportion 546. While the illustrated embodiment has three posts 552, anynumber of posts capable of connecting the ring portion to the deflectionportion should be considered to be within the scope of this invention.The spacings between the posts 552 define flow passages 554 for therefrigerant to flow through. The diverter/diffuser portion 546 has aconical outer surface. Alternatively the deflecting portion can have afrusto-conical outer surface. The conical outer surface deflects therefrigerant flowing out of the fluid flow opening 543 towards thesidewall. Due to the conical or frusto-conical surface having a radiallyexpanding surface, the diverter/diffuser portion 546 not only re-directsthe refrigerant, but as the refrigerant flows dowardly along theradially expanding surface, the refrigerant is spread out to diffuse therefrigerant. The deflector may be made from molded plastic, cast zinc,stamped aluminum or other materials.

[0034]FIG. 10 illustrates a fifth embodiment of a fluid inlet pipeassembly 640 according to the present invention. The fluid inlet pipeassembly 640 is attached to the top wall 628 of the accumulator housing622. The fluid inlet pipe assembly includes a tubular vertical portion642, a tubular diverter portion 646 and a curved portion 644 connectingthe vertical portion 642 to the diverter portion 646. The verticalportion 642 has an axis approximately parallel with the axis of theaccumulator housing 622. To allow the inlet end 670 of the outlet pipeassembly 660 to be located near the ceiling of the accumulator housing622, the axis of the vertical portion 642 is offset from the inlet end670 of the outlet pipe assembly 660. In other words, the axis of thevertical portion 642 does not intersect the inlet end 670 of the outletpipe assembly 660. Such an arrangement allows the inlet end 670 of theoutlet pipe assembly 660 to be located adjacent to the vertical portion642 of the inlet pipe 640, rather than, below the vertical portion 642of the inlet pipe 640.

[0035] The axis of the diverter portion 646 is at an angle approximately90 degrees from the axis of the vertical portion 642. By bending thepipe for forming the inlet pipe assembly 640 at an angle approximately90 degrees, the flow of the inlet refrigerant mixture is directedtowards the side wall 634. By directing the inlet refrigerant mixturetowards the side wall 634, the liquid refrigerant is able to flowdownwardly along the side wall 634 to the bottom sump portion of theaccumulator housing 622.

[0036] The terminal end of the diverter portion 646 defines the outletend 648 of the fluid inlet pipe assembly 640. The outlet end 648 of thefluid inlet pipe assembly 640 is formed by making an angular cut acrossthe diverter portion 646 such that the plane of the cut is approximatelyparallel to the axis of the vertical portion 642 and the cut is madebeyond the center point C₂ defining the curvature of the curved portion644.

[0037] In addition, it is desirable for the distance from the inlet end670 of the outlet fluid pipe assembly 660 to the top wall 628 of theaccumulator housing to be greater than the distance from the outlet end648 of the inlet fluid pipe assembly 640 to the top wall 628 of theaccumulator housing. This arrangement reduces the possibility of inletrefrigerant from unintentionally entering the inlet end 670 of theoutlet fluid pipe assembly 660.

[0038]FIG. 11 illustrates a sixth embodiment of a fluid inlet pipeassembly 740 according to the present invention. The fluid inlet pipeassembly 740 is attached to the top wall 728 of the accumulator housing722. The fluid inlet pipe assembly includes a tubular vertical portion742 and a tubular diverter/diffuser portion 746. The tubulardiverter/diffuser portion includes a tubular horizontal sub-portion 746b and a curved sub-portion 746 a connecting the vertical portion 742 tothe horizontal sub-portion 746 b. The vertical portion 742 has an axisapproximately parallel with the axis of the accumulator housing 722. Toallow the inlet end 770 of the outlet pipe assembly 760 to be locatednear the ceiling of the accumulator housing 722, the axis of thevertical portion 742 is offset from the inlet end 770 of the outlet pipeassembly 760. In other words, the axis of the vertical portion 742 doesnot intersect the inlet end 770 of the outlet pipe assembly 760. Such anarrangement allows the inlet end 770 of the outlet pipe assembly 760 tobe located adjacent to the vertical portion 742 of the inlet pipe 740,rather than, below the vertical portion 742 of the inlet pipe 740.

[0039] The axis of the horizontal sub-portion 746 b is at an angleapproximately 90 degrees from the axis of vertical portion 742. Theterminal end of the fluid inlet pipe assembly 740 defines an outlet end748. The outlet end 748 of the fluid inlet pipe assembly 740 is formedby making an angular cut across the diverter/diffuser portion 746 suchthat the bottom edge 747 a of the diverter/diffuser portion 746 extendsfurther from the axis of the vertical portion 742 than the top edge 747b of the diverter/diffuser portion 746. It is preferable that the bottomedge 746 a extends beyond the center point C₃ defining the curvature ofthe curved sub-portion 746 a and the top edge 746 b be located betweenthe tubular vertical portion 742 and the center point C₃. The angle βfrom the plane of the cut forming the outlet end 748 to a planeperpendicular to the axis of the horizontal sub-portion 746 b ispreferably between 30 degrees to 60 degrees, and more preferably atapproximately 45 degrees. By forming the outlet end 748 with the bottomedge 747 a of the diverter/diffuser portion 746 extending further fromthe axis of the vertical portion 742 of the diverter/diffuser portion746, the outlet end 748 is directed towards the side wall 734 andupwardly towards the ceiling 730 of the accumulator housing 722. Bydirecting the inlet refrigerant mixture towards the side wall 734, theliquid refrigerant is able to flow downwardly along the side wall 734 tothe bottom sump portion of the accumulator housing.

[0040] Furthermore, since the plane of the cut forming the outlet end748 is at angle from the plane perpendicular to the axis of thehorizontal sub-portion 746 b, the outlet end 748 of the fluid inlet pipeassembly 740 has a cross-sectional area greater than the averagecross-sectional area perpendicular to the axis of the vertical portion742. With the outlet end 748 having a greater cross-sectional area, theoutlet end 748 is able to act as a diffuser diffusing the flow ofrefrigerant coming out the outlet end 748; thus, reducing or preventingturbulent flow of refrigerant.

[0041] In addition, it is desirable for the distance from the inlet end770 of the outlet fluid pipe assembly 760 to the top wall 728 of theaccumulator housing to be greater than the distance from the outlet end748 of the inlet fluid pipe assembly 740 to the top wall 728 of theaccumulator housing. This arrangement reduces the possibility of inletrefrigerant from unintentionally entering the inlet end 770 of theoutlet fluid pipe assembly 760.

[0042] While the above embodiments of the present invention areillustrated with the trumpet shaped outlet tube, the use of the trumpetshaped outlet tube is not necessary to recognize the improvedperformance of an accumulator using an inlet tube assembly in accordanceto the present invention. Improved performance of an accumulator usingan inlet tube assembly in accordance to the present invention can alsobe recognized with a baffle attached to the accumulator housing or tothe outlet tube. Furthermore, while the improved performance of theaccumulator using an inlet tube assembly in accordance to the presentinvention is more evident with the inlet tube assembly attached to thetop wall, an improved performance of the accumulator using an inlet tubeassembly in accordance will also be recognized with the inlet tubeassembly attached to the side wall.

[0043] In addition to improving the performance of the accumulator byusing an inlet tube assembly in accordance to the present invention todivert the refrigerant toward the side wall and downwardly whilediffusing the refrigerant to reduce turbulent, turbulent flow of therefrigerant can also be reduced by an improved flow path defined in theinlet fitting with fewer sharp edges. As stated in the backgroundsection, turbulent flow may also be caused by the refrigerant flowingthrough the flow passage defined within an inlet fitting. FIGS. 12 and13 illustrate a typical inlet fitting 36 with a bent flow path. Theinlet fitting 36 defines a first straight fluid passage 60 and a secondstraight fluid passage 64, wherein the first straight fluid passage 60intersects the second straight fluid passage 64 at an intersection point68. The first straight fluid passage 60 has a cylindrical bore 70 and aconical terminal end 62. The second straight fluid passage 64 has acylindrical bore 72 and a conical terminal end 66. The cylindrical bore70 of the first straight fluid passage 60 has a diameter D₁ greater thanthe diameter D₂ of the cylindrical bore 72 of the second straight fluidpassage 64. To assure that the intersection of the first fluid passage60 with the second fluid passage 64 does not restrict the flow ofrefrigerant flowing through the bent flow path, the cylindrical bore ofthe first fluid passage and the cylindrical bore of the second fluidpassage extend at least to the intersection point 68. However, due tothe conical terminal end 62 of the first fluid passage 60 and/or theconical terminal end 66 of the second fluid passage 64, a protrusion 74may be defined near the intersection point 68. The protrusion 74 and thetransition from the cylindrical bores 70, 72 to the correspondingconical ends 62, 66 create sharp edges that may cause turbulence andpressure drop in the refrigerant flowing through the bent path of theinlet fitting 36.

[0044]FIGS. 14 and 15 illustrate an inlet fitting with a bent flow pathaccording to the second aspect of the present invention. The inletfitting 836 in according to the present invention defines a firststraight fluid passage 860 and a second straight fluid passage 864,wherein the first straight fluid passage 860 intersects the secondstraight fluid passage 864 at an intersection point 868. The firststraight fluid passage 860 has a cylindrical bore 870 and a concaveterminal end 862. The second straight fluid passage 864 has acylindrical bore 872 and a concave terminal end 866. To assure that theintersection of the first fluid passage 860 with the second fluidpassage 864 does not restrict the flow of refrigerant flowing throughthe bent flow path, the cylindrical bore of the first fluid passage andthe cylindrical bore of the second fluid passage extend at least to theintersection point 868. Since the terminal ends of the fluid passages860, 864 are defined by concave or rounded surfaces 862, 866, sharpnotches and sharp transition edges from the cylindrical bores to the endsurfaces are essentially eliminated in the bent flow path in the inletfitting 836 in accordance to the present invention. A flow path having afull-radius shaped intersection improves the flow and reduces turbulenceand pressure drop. One method to create such concave terminal ends is touse ball end cutters with full-radius shape drill points, instead of theindustry typical cutter with sharp conical drill points. It ispreferable that the inlet fitting 836 have the diameter D₄ of thecylindrical bore 872 of the second fluid passage 864, in the order offluid path, be equal or greater than the diameter D₃ of the cylindricalbore 870 of the first fluid passage 860 to prevent any restrictions inthe fluid flow path. It is also preferable that the inner diameter ofthe section of the inlet pipe assembly inserted into the second fluidpassage be equal or greater than the diameter D₃ of the cylindrical bore870 of the first fluid passage 860 to prevent any restrictions in thefluid flow path.

[0045] It should be noted that while the use of a diverter/diffuserportion in accordance to the first aspect of the present invention canbe used in conjunction with an inlet fitting in accordance to the secondaspect of the present invention to increase the overall performance ofthe accumulator, the diverter/diffuser portion in accordance to thefirst aspect of the present invention and the inlet fitting inaccordance to the second aspect of the invention can be usedindependently and still be able recognize an increase in performance ofthe accumulator.

[0046] Various features of the present invention have been describedwith reference to the above embodiments. It should be understood thatmodification may be made without departing from the spirit and scope ofthe invention as represented by the following claims.

1. An accumulator for use in a motor vehicle air conditioning system,said accumulator comprising: an accumulator housing having a top wall, abottom wall, and a side wall connecting the top wall to the bottom wall;an outlet fluid pipe assembly having an inlet end; and an inlet fluidpipe assembly includes a tubular first portion and a diverter/diffusingportion configured to direct refrigerant flowing through said firstportion towards the sidewall and downwardly away from the top wall ofthe accumulator housing, said first tubular portion having an axisoffset from said inlet end of said outlet fluid pipe assembly.
 2. Theaccumulator as claimed in claim 1 wherein said inlet fluid pipe has anoutlet opening, the distance from said inlet end of the outlet fluidpipe assembly to the top wall of the accumulator housing is greater thanthe distance from the outlet end of the inlet fluid pipe assembly to thetop wall of the accumulator housing.
 3. The accumulator as claimed inclaim 1 wherein said inlet fluid pipe assembly is mounted to the topwall of the accumulator housing.
 4. The accumulator as claimed in claim1 wherein said outlet fluid pipe assembly is mounted to the sidewall ofthe accumulator housing.
 5. The accumulator as claimed in claim 1wherein said outlet fluid pipe assembly is U-shaped.
 6. The accumulatoras claimed in claim 1 wherein a single pipe forms both the first portionand said diverter/deflector portion.
 7. The accumulator as claimed inclaim 1 wherein said first portion of said inlet pipe assembly has anaxis approximately parallel to the axis of the accumulator housing. 8.The accumulator as claimed in claim 7 wherein said diverter/diffuserportion of said inlet pipe assembly has an axis greater than 0 degreeand less than 90 degrees from the axis of the first portion.
 9. Theaccumulator as claimed in claim 8 wherein said diverter/diffuser portionhas an axis between 10 to 80 degrees from the axis of the first portion.10. The accumulator as claimed in claim 9 wherein said diverter/diffuserportion has an axis between 15 to 45 degrees from the axis of the firstportion.
 11. The accumulator as claimed in claim 1 wherein saiddiverter/diffuser portion has an outlet opening, the cross-sectionalarea of the outlet opening is greater than the average cross-sectionalarea perpendicular to the axis of the first portion.
 12. The accumulatoras claimed in claim 11 wherein the average cross-sectional areaperpendicular to the axis of the diverter/diffuser portion isapproximately equal to the average cross-sectional area of the axis ofthe axis of the first portion.
 13. The accumulator as claimed in claim 1wherein the plane of said outlet opening is approximately parallel tothe axis of the accumulator housing.
 14. The accumulator as claimed inclaim 1 wherein the plane of said outlet opening is approximatelyparallel to the axis of the first portion.
 15. The accumulator asclaimed in claim 6 wherein said diverter/diffuser portion is formed byunfolding a section of said single pipe.
 16. The accumulator as claimedin claim 1 wherein said diverter/diffuser portion is a separatecomponent attached to the first portion.
 17. The accumulator as claimedin claim 16 wherein said diverter/diffuser portion is conical orfrusto-conical shaped.
 18. The accumulator as claimed in claim 16wherein said inlet pipe assembly further includes a mounting ring and aplurality of posts connecting said ring to said diverter/diffuserportion.
 19. An accumulator assembly for use in a motor vehicle airconditioning system, said accumulator assembly comprising: anaccumulator housing having a top wall, a bottom wall, and a side wallconnecting the top wall to the bottom wall; an outlet fluid pipeassembly; an inlet fluid pipe assembly; and an inlet fitting attached tosaid top wall of said accumulator housing, a first straight fluidpassage having a concave terminal end defined in said inlet fitting, asecond straight fluid passage having a concave terminal end defined insaid inlet fitting, said inlet fluid pipe assembly has a tubular portioninsertable into an opening of said second straight fluid passage, saidfirst straight fluid passage intersects said second fluid passage toallow refrigerant to flow from said first straight fluid passage to saidsecond straight fluid passage and into said inlet fluid pipe assembly.20. An accumulator assembly as claimed in claim 19 wherein the diameterof said first straight passage is approximately equal to the innerdiameter of said tubular portion of said inlet fluid pipe assembly. 21.An accumulator assembly as claimed in claim 19 wherein the diameter ofsaid first straight passage is less than the inner diameter of saidtubular portion of said inlet fluid pipe assembly.
 22. An accumulatorfor use in a motor vehicle air conditioning system, said accumulatorcomprising: an accumulator housing having a top wall, a bottom wall, anda side wall connecting the top wall to the bottom wall; an outlet fluidpipe assembly having an inlet end; and an inlet fluid pipe assemblyincludes a tubular first portion and a diverter/diffusing portionconfigured to direct refrigerant flowing through said first portiontowards the sidewall and upwardly towards the top wall of theaccumulator housing, said first tubular portion having an axis offsetfrom said inlet end of said outlet fluid pipe assembly.
 23. Theaccumulator as claimed in claim 22 wherein said diverter/diffuserportion has an outlet opening, the cross-sectional area of the outletopening is greater than the average cross-sectional area perpendicularto the axis of the first portion.
 24. The accumulator as claimed inclaim 23 wherein the bottom edge of the diverter/diffuser portionextends further from the axis of the vertical portion than the top edgeof the diverter/diffuser portion from the axis of the vertical portion.25. The accumulator as claimed in claim 23 wherein the diverter/diffuserportion includes a sub-portion, the outlet end defines a plane between30 degrees to 60 degrees from a plane perpendicular to the axis of thesub-portion.